Descôteaux was born in Sainte-Monique, Quebec, on 18 November 1906. Her parents were Joseph Descôteaux (1863–1931) and Maria Denis (c.1869–1953). She decided to commit her life to Roman catholic faith, and entered the convent of Roman catholic Assumption sisters (French: Sœurs de l’Assomption) in August 1933, aged 26. For decades, she taught English and music with predilection to singing. She was the second oldest nun in her convent, younger only than Judith Pinard (1898–2009).
Isabelle Descoteaux passed away in Nicolet, Quebec, Canada, on 15 September 2017, at age of 110 years, 301 days.
At the time of death, she was the oldest living nun in Canada, and country’s third-oldest nun ever, behind Anne Samson (1891–2004) and Judith Pinard (1898–2009).
* “DESCÔTEAUX, Isabelle” – Familles Dupuis et Harvey
* “Une supercentenaire dans la region” – Le Nouvelliste, 3 December 2016